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Brian W
Brian W, Master Chrysler Tech.
Category: Dodge
Satisfied Customers: 585
Experience:  Chrysler Gold Certified, Ase Certified
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98 Dodge Dakota: 6cyl..4x4..a sensor, or the tranny

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'98 Dodge Dakota 6cyl. 4x4.
P0740 TCC Circuit Malfunction. Is this just a problem with a sensor, or the tranny. Seems to be shifting fine. P0305 Cylinder 5 misfire code also came up.

The TCC is the torque converter control solenoid. That's is what's used to give you overdrive.

That really needs to be checked out by a competent trans shop to determine what's wrong in the circuit.

The cylinder misfire is usually caused by the secondary ignition components, like the plugs and wires. If it's due for a tune up, replace them all.

Customer: replied 9 years ago.
Reply to Chrysler man's Post: The overdrive occasionally turns off by itself, usually when going up a hill/grade. When I stop and restart the truck, the overdrive will re-engage. Is this another sign that the selenoid is bad.
I didn't say the solenoid was bad. There is a problem in the circuit. There are other possibilities besides the solenoid.
Customer: replied 9 years ago.
Relist: I prefer a second opinion.
I would like to know more specifically what I can do to assess and fix the problem myself, before I have to take it to the shop, otherwise I would have done that already. I have also noticed some tranny fluid leaking but can't tell specifically where from. The fluid is red and clear.

The solenoid is internal to the transmission and it's going to require special equipment and knowledge to test the circuit so it's not something you can do yourself.

 

 

 

 

 

Hello, I am reviewing trouble code p0740 and one of the possible causes for this code is actually a misfire. This code is set if the desired drop in engine rpm when the tcc solinoid, is near maxiumium duty cycle. The first thing they have you do is check for any misfire codes and repair, first. This affects rpm while in "lock up".

I had a 97 Dakota and they are known for ignition wires arcing. Also the tcc solinoid does not control overdrive as was explained to you earlier.

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The previous answer is incorrect.

As you can see in the flow chart for that code which is supplied by the manufacturer, it lists all the possible causes of that code and misfire is not one of them

 

graphic

As you can see, The description is from a tsb back in 1997. And not even the code # XXXXX may indeed have a trans issue. But I recommend repairing the misfire first, before you go to a transmission shop, as suggested by the other expert.

Symptom:

P-0740 TORQ CONV CLU, NO RPM DROP AT LOCKUP

When Monitored and Set Condition:

P-0740 TORQ CONV CLU, NO RPM DROP AT LOCKUP

When Monitored: Continuously with the key on. Not in Park or Neutral and no other MIL

(trouble codes) illuminations.

Set Condition: If the TCC cannot achieve the desired drop in engine RPM when the TCC

solenoid is near maximum duty cycle. Three consecutive bad tests are required to set the

code.

POSSIBLE CAUSES

MISFIRE TROUBLE CODE SET

VEHICLE STALLS (TORQUE CONVERTER CLUTCH SOLENOID)

TORQUE CONVERTER CLUTCH SHAFT(S)/SEAL DEFECTIVE

TRANSMISSION FLUID CONTAMINATED

NO PROBLEMS DIAGNOSED

TCC SOLENOID WIRING HARNESS OBSERVABLE DEF

TORQUE CONVERTER CLUTCH DEFECTIVE

TORQUE CONVERTER CLUTCH HYDRAULIC CIRCUIT DAMAGED

That \flow chart most certainly WAS for a PO740 and was issued by Chrysler.

You can see the test number next to the PO740

graphic

 

 

 

The previous test appears to be edited. As it states for the criteria for setting this code is that no other codes can be illuminated meaning it CANNOT have a misfire code for it to set

 

Quote:

P-0740 TORQ CONV CLU, NO RPM DROP AT LOCKUP

When Monitored: Continuously with the key on. Not in Park or Neutral and no other MIL

(trouble codes) illuminations.

Set Condition: If the TCC cannot achieve the desired drop in engine RPM when the TCC

solenoid is near maximum duty cycle. Three consecutive bad tests are required to set the

code.


Customer: replied 9 years ago.
Reply to Brian W's Post: I began to replace the plugs and wires until one of the spark plugs came apart. The whole porcelain center came out, from top to bottom, and left the threads stuck in the engine. I just changed them about a year ago. What are my options? How is this problem fixed?

This is done using a special tool called an easy out extractor. This tool tightens itself inside the threads, inside the leftover portion of the spark plug.

http://search.ebay.com/easy-out-tool_W0QQfnuZ1QQfsooZ1QQfsopZ3QQxpufuZx I know craftsman makes these.

______________________________________________________________________

Brian W, Master Chrysler Tech.
Category: Dodge
Satisfied Customers: 585
Experience: Chrysler Gold Certified, Ase Certified
Brian W and 3 other Dodge Specialists are ready to help you

If the threads were seized enough to cause the plug to break in half, it's highly unlikey that any extracter will have any effect on it.

It will likely have to be drilled out and the head should be removed to do that.